As some may have noticed, on the stock gearbox selector housing there is a little plastic bush that allows the lever to guide the selector shaft in and out. I have always though this bush looked like it was not designed to do what it actually does (perhaps from another vehicle?) and there is a lot of play that must contribute to miss shifts to some extent.
A video with a fitting guide can be seen below!
To solve the problem and strengthen this area Ross Sport has manufactured an uprated tight tolerance version of the bush that spreads the load across the shaft. They are CNC machined from Delrin and extremely tough and heat resistant.
Pic showing selector housing:
Pic showing stock bush in place:
Pic showing Stock bush V's Uprated (black one)
Pic Showing uprated bushing clipped to selector shaft Vs Stock
Pic showing uprated bush installed: